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BrianG · 03.28.2011, 10:55 AM

<rant>

Charger requirements are getting pretty stupid IMO.

For ~400w and less chargers, I can understand (but don't necessarily agree) why they require a 12v supply so that they can be used off a 12v car battery in the field.

For the 500w+ chargers that accept 12v or ~24v; you can't get the full capability at 12v or in the field off your car anyway, so you are forced to get a high price 24v+ supply.

But honestly, how much would it really cost to add in a switching PS that accepts either 12v DC or 120/240v AC? Circuit-wise, it's not all that complex; after all, all of these chargers use a switching PS internally already to turn that 12v into whatever voltage the battery needs. So, put the necessary supply in these things and charge extra. The result is safer; Joe Six-Pack, who doesn't know a resistor from a capacitor, won't be forced to fork over big $$$ for a big supply, or attempt to cobble something together, possibly unsafe, like certain companies. Yeah, the charger will be physically larger, but not really once you factor in the external PS. And all chargers could still have direct 12v DC input for field use (reduced output for the bigger chargers).

And while on the subject, why is the 12v input limited to 40-50A? You can't tell me they don't make FETs capable of switching more than that (look inside any ESC)? Maybe they can't wind their internal transformer with wires that'll handle it? Nope. Look at any really high power car audio amp; some of those transformers can handle well over 100A. Maybe it's so the dummies won't drain their car batteries in the field? I don't buy that either because even at 40A limit, a typical car battery (especially when not brand new) will be drained in less than an hour anyway.

I say make all chargers accept 12v DC (with no output limitation) AND 120/240vAC input. There is NO legitimate reason not to.

</rant>

	(#89)
BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	03.28.2011, 10:55 AM <rant> Charger requirements are getting pretty stupid IMO. For ~400w and less chargers, I can understand (but don't necessarily agree) why they require a 12v supply so that they can be used off a 12v car battery in the field. For the 500w+ chargers that accept 12v or ~24v; you can't get the full capability at 12v or in the field off your car anyway, so you are forced to get a high price 24v+ supply. But honestly, how much would it really cost to add in a switching PS that accepts either 12v DC or 120/240v AC? Circuit-wise, it's not all that complex; after all, all of these chargers use a switching PS internally already to turn that 12v into whatever voltage the battery needs. So, put the necessary supply in these things and charge extra. The result is safer; Joe Six-Pack, who doesn't know a resistor from a capacitor, won't be forced to fork over big $$$ for a big supply, or attempt to cobble something together, possibly unsafe, like certain companies. Yeah, the charger will be physically larger, but not really once you factor in the external PS. And all chargers could still have direct 12v DC input for field use (reduced output for the bigger chargers). And while on the subject, why is the 12v input limited to 40-50A? You can't tell me they don't make FETs capable of switching more than that (look inside any ESC)? Maybe they can't wind their internal transformer with wires that'll handle it? Nope. Look at any really high power car audio amp; some of those transformers can handle well over 100A. Maybe it's so the dummies won't drain their car batteries in the field? I don't buy that either because even at 40A limit, a typical car battery (especially when not brand new) will be drained in less than an hour anyway. I say make all chargers accept 12v DC (with no output limitation) AND 120/240vAC input. There is NO legitimate reason not to. </rant>